(Numbers in brackets refer to the general plan of the Villa)
In order to build the Villa, the tufa bank was deeply dug, thus providing tufa and pozzolana, the main building materials.
In the Bulgarini estate are still visible some remnants of an ancient aqueduct, which probably was linked to one of the great public aqueducts that brought water from Tivoli to Rome, drawing it from the Aniene river.
Villa Hadriana had a vast and extensive subterranean road network, which was used by the slaves to reach the heating plants of the thermal buildings or to go from one building to the other without being seen. There also was a long subterranean road-way (more than four kilometers long), dug in the tufa bank and lighted by openings in its vaults (oculi), called Great Trapezium (Grande Trapezio) (n. 34).
In the Historia Augusta it is said that the Emperor Hadrian wanted to reproduce in his Villa at Tivoli the most celebrated monuments and places of greek antiquity, such as the Accademia, Lyceum and the Inferi. The scholars who studied the Villa always tried to match what they found with that description, and this lead to the birth of a series of fantastic names, most of which were invented by Ligorio but are still in use, even if of dubiuous significance (think of Teatro Marittimo / Maritime Theatre). These traditional names are mantained in this site to avoid misunderstandings giving new names.